Etsuko is from the Japanese 悦子 / 越子 (Etsuko — etsu joy/delight + ko child — joy child, delighted child). Etsuko is one of the Japanese feminine names — central to traditional Japanese heritage. The Japanese etsu (joy) is one of the Japanese virtue-naming roots. Japanese feminine name reflecting Japanese cultural heritage.
Etsuko does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Etsuko reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.